Rounding Numbers

Transcript Rounding Numbers

Rounding Numbers

Rounding Numbers ♦ Sometimes, we don’t need a number to be completely accurate. In fact, sometimes we prefer it to be rounded:

Rounding Numbers ♦ Sometimes, we don’t need a number to be completely accurate. In fact, sometimes we prefer it to be rounded: Ex) If you asked a friend how far it was to his house, how would you feel if he said, “Oh, it’s about 17.62955 kilometres away.”

Rounding Numbers ♦ Ex) Round 16.

8 722 to the nearest tenth.

Rounding Numbers ♦ Ex) Round 16.

8 722 to the nearest tenth.

Ask, “Is that number closer to 16.8 or 16.9 ?”

Rounding Numbers ♦ Ex) Round 16.

8 722 to the nearest tenth.

Ask, “Is that number closer to 16.8 or 16.9 ?” How do you decide?

Rounding Numbers ♦ Ex) Round 16.

8 7 22 to the nearest tenth.

Ask, “Is that number closer to 16.8 or 16.9 ?” How do you know?

Check the “key” digit to the right of the tenths column.

Rounding Numbers ♦ Ex) Round 16.

8 7 22 to the nearest tenth.

Ask, “Is that number closer to 16.8 or 16.9 ?” How do you decide?

Check the “key” digit to the right of the tenths column.

THINK: Is 87 closer to 80 or 90 ?

Rounding Numbers ♦ Ex) Round 16.

8 7 22 to the nearest tenth.

Ask, “Is that number closer to 16.8 or 16.9 ?” How do you decide?

Check the “key” digit to the right of the tenths column.

THINK: Is 87 closer to 80 or 90 ?

The number equals 16.9 rounded to the nearest tenth.

Rounding Numbers RULE:

Rounding Numbers RULE: Locate the position of the final digit.

If the key digit is 5 or greater, then round the final digit up. Otherwise, the final digit stays the same.